Plasma dynamics in radial wire array Z-pinches

Summary form only given. We describe experiments on the MAGPIE facility (1 MA, 250ns) with radial wire array Z-pinches, in which the wires form a wheel-spoke configuration. Variation of the global magnetic field and the corresponding JxB force along the wires in this configuration allows studying an effect of the global magnetic field on the ablation rate of the wires. The knowledge of the scaling of the ablation rate is important for interpretation of the dynamics of wire array Z-pinch plasma radiation sources. The parameters of the coronal plasma, which is pushed away from the wire cores by the JxB force, were measured using laser interferometry, X-ray and XUV imaging. The complete ablation of the wires near the inner electrode, where the ablation rate is the highest, triggers an axial acceleration of the plasma. This leads to formation of plasma configuration similar to a plasma focus and generation of the X-ray pulse. The results of the experiments with tungsten and aluminium radial wire arrays are presented.